World journal of microbiology & biotechnology incorporating the MIRCEN Journal of applied microbiology and biotechnology/World journal of microbiology & biotechnology, Jul 2, 2024
The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilizati... more The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilization of red cabbage extract (RCE) within bacterial cellulose (BC) to detect contamination and gamma radiation exposure in cucumbers. The results obtained show a sensitivity to pH changes for RCE in its aqueous form and that incorporated within BC films (RCE-BC), both showed color change correlated to bacterial growth (R 2 = 0.91), this was supported with increase in pH values from 2 to 12 (R 2 = 0.98). RCE and RCE-BC exposure to gamma radiation (0, 2.5, 5, 10, 15, 20, 25 kGy) resulted in gradual decrease in color that was more evident in RCE aqueous samples. To sense bacterial contamination of cucumbers, the total count was followed at 0, 5, 10 and 15 days in cold storage conditions and was found to reach 9.13 and 5.47 log cfu/mL for non-irradiated and 2 kGy irradiated samples, respectively. The main isolates detected throughout this storage period were identified as Pseudomonas fluorescens, Erwinia sp. Pantoea agglomerans using matrix assisted laser desorption ionization-time of flight-ms (MALDI-TOF-MS). Bacterial growth in stored irradiated cucumbers was detected by color change within 5 and 10 days of storage, after which there was no evident change. This is very useful since contamination within the early days of storage cannot be sensed with the naked eye. This study is the first to highlight utilizing RCE and RCE-BC as eco-friendly pH-sensing indicator films for intelligent food packaging to detect both food contamination and gamma preservation for refrigerator stored cucumbers.
The present study investigates how well the light quality (white, blue, and red light) affects th... more The present study investigates how well the light quality (white, blue, and red light) affects the growth and biochemical profiling of freshwater microalga Scenedesmus obliquus grown on aquaculture wastewater as a nutrient source in a biocathode microbial fuel cell (MFC). The findings show that the electrochemical behaviour of the MFCs varied with the use of different wavelengths, suggesting that light quality and photosynthetic evolved oxygen increased MFC voltage. Sc. obliquus showed the highest percentage of nutrient removal for blue light-operated biocathode MFC. Blue light maximized biomass production with a cell density of 1.54 ± 0.065 OD680 and Chl-a concentration of 12 ± 1.2 mgL − 1 during 6-day cultivation. Valorization of aquaculture using MFC proved successful in nutrient recovery and microalgae biomass production, primarily upon exposure to blue light.
The increase in using antibiotics, especially Azithromycin have increased steadily since the begi... more The increase in using antibiotics, especially Azithromycin have increased steadily since the beginning of COVID19 pandemic. This increase has led to its presence in water systems which consequently led to its presence upon using this water for irrigation. The aim of the present work is to study the impact of irrigation using Azithromycin containing water on soil microbial community and its catabolic activity in the presence of phenolic wastes as compost. Wild berry, red grapes, pomegranate, and spent tea waste were added to soil and the degradation was monitored after 5 and 7 days at ambient and high temperatures. The results obtained show that at 30 °C, soil microbial community collectively was able to degrade Azithromycin, while at 40 °C, addition of spent tea as compost was needed to reach higher degradation. To ensure that the degradation was biotic and depended on degradation by indigenous microflora, a 25 kGy irradiation dose was used to kill the microorganisms in the soil and...
Textile wastewater still poses a huge environmental problem due to its high water consumption and... more Textile wastewater still poses a huge environmental problem due to its high water consumption and high effluent release that is full of toxic chemicals. In the present study, different approaches were studied to layout an operating procedure for textile wastewater treatment in order to obtain treated wastewater that is safe for non-potable uses. Our approach depended on (1) co-substrate to biostimulate indigenous microbial textile wastewater community by adding Tryptone Soy Broth (TSB) and TSB supplemented with 1% glucose, (2) co-culture (bioaugmentation) with Bacillus spizizenii DN cells (previously isolated, identified and characterized as efficient decolorizing bacteria), and (3) co-metabolites using Bacillus spizizenii DN metabolites. The obtained results show that using Bacillus spizizenii DN cells resulted in 97.78% decolorization while adding Bacillus spizizenii DN metabolites resulted in 82.92% decolorization, both after 48 h incubation under microaerophilic conditions. The ...
MFCs have the potential to revolutionise wastewater treatment and catalyse a change in attitude t... more MFCs have the potential to revolutionise wastewater treatment and catalyse a change in attitude towards wastewater as a commodity. It has been observed that domestic wastewater contains approximately 7.6 kJ/L of energy (Heidrich et al., 2011). In large-scale settings, wastewater could be used as an energy resource, offering huge savings in terms of cost and environmental burden. The major challenges facing the implementation of MFCs into wastewater treatment are scale up and energy harvesting/storage. In this study, a modular 20L air-breathing microbial fuel cell was developed alongside a smart energy harvesting (EH) system incorporating AI. The 20L air breathing MFC consists of modular cathode cassettes that enables easy maintenance and scale up to suit adaptive or changing end user requirements. PVDF/Stainless steel mesh cathodes are fabricated using phase inversion and oxygen reduction reaction catalysts incorporated in the polymeric matrix. Custom made carbon fibre brush electro...
Microbial biocathodes are gaining interest due to their low cost, environmentally friendliness an... more Microbial biocathodes are gaining interest due to their low cost, environmentally friendliness and sustainable nature. In this study, activated sludge from a textile treatment plant was enriched by chronoamperometry over 70 days to select for electroactive bacteria for use as a cathode catalyst in microbial fuel cells (MFC) designed for azo dye degradation in the anode chamber. The resultant biofilm produced an average peak current of 0.7 mA during the enrichment and produced a maximum power density of 64.6±3.5 mW m-2 compared to platinum (72.7±1.2 mW m-2) in a MFC. The acclimated biocathode eliminated start-up lag and decreased the activation overpotential at the cathode. The rate of dye decolourisation at the anode was similar in both platinum and biocathode MFCs. Activation losses were lower for the biocathode than with platinum suggesting that the bacteria act as true cathode catalysts. The microbial community analysis of the initial sludge sample and enriched samples revealed t...
Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquacultur... more Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquaculture industry as an antifungal agent, however, it can accumulate in fish and pose toxicity. The present work aims to remove MG in Microbial Fuel Cell (MFC) as a sustainable and eco-friendly solution. Out of six samples, the highest malachite green degradation was obtained by a sample obtained from Robiki tannery site in agar plates in 24 h at 37 °C. Robiki sample was used to inoculate the anodic chamber in Microbial Fuel cell, the resulting average electricity production was 195.76 mV for two weeks. The decolorization average was almost 88%. The predominant bacteria responsible for MG decolorization and electricity production were identified using 16S rRNA as Shewanella chilikensis strain MG22 (Accession no. OP795826) and formed a heavy biofilm on the anode. At the end of the decolorization process, MG was added again for re-use of water. The results showed efficiency for re-use 3 times. To...
World Journal of Microbiology and Biotechnology, 2024
The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilizati... more The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilization of red cabbage extract (RCE) within bacterial cellulose (BC) to detect contamination and gamma radiation exposure in cucumbers. The results obtained show a sensitivity to pH changes for RCE in its aqueous form and that incorporated within BC films (RCE-BC), both showed color change correlated to bacterial growth (R 2 = 0.91), this was supported with increase in pH values from 2 to 12 (R 2 = 0.98). RCE and RCE-BC exposure to gamma radiation (0, 2.5, 5, 10, 15, 20, 25 kGy) resulted in gradual decrease in color that was more evident in RCE aqueous samples. To sense bacterial contamination of cucumbers, the total count was followed at 0, 5, 10 and 15 days in cold storage conditions and was found to reach 9.13 and 5.47 log cfu/mL for non-irradiated and 2 kGy irradiated samples, respectively. The main isolates detected throughout this storage period were identified as Pseudomonas fluorescens, Erwinia sp. Pantoea agglomerans using matrix assisted laser desorption ionization-time of flight-ms (MALDI-TOF-MS). Bacterial growth in stored irradiated cucumbers was detected by color change within 5 and 10 days of storage, after which there was no evident change. This is very useful since contamination within the early days of storage cannot be sensed with the naked eye. This study is the first to highlight utilizing RCE and RCE-BC as eco-friendly pH-sensing indicator films for intelligent food packaging to detect both food contamination and gamma preservation for refrigerator stored cucumbers.
Biofilm-mediated strategy was studied for ZnO nanoparticle removal from aqueous media. Bacillus s... more Biofilm-mediated strategy was studied for ZnO nanoparticle removal from aqueous media. Bacillus subtilis isolated from the soil rhizosphere was selected based on its high viscosity (133 Pa/s) of the cultivated culture and biofilm formation. The bacterium was exposed to gamma-irradiation to enhance EPS production along with its cultivation in EPS-producing media. The results show an increase in viscosity that reached 160 Pa/s at 2 kGy. EPS production increased from 4.45 to 7.95 mg/mL and the protein/carbohydrate ratio increased from 3 to 4.4 which reflects the stickiness of EPS. Thermal Gravimetric Analysis (TGA) showed 2 phase weight loss for gamma irradiated EPS and defined protein peaks when characterized using Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF). Native and gamma-irradiated Bacillus subtilis cells with their enhanced EPS were grown as a biofilm on sterile waste gauze fabric, Scanning Electron Microscopy (SEM) showed an increased biofilm attachment in gamma-irradiated samples. The latter was used for the removal of ZnO NP from aqueous media. Energy dispersive X-ray (EDX) mapping confirms that ZnO NPs were entrapped within the carbon and oxygen elements forming the biofilm with net intensities of 14.04, 1713, and 1190, respectively. The results confirm that biofilm-mediated strategy is effective in nanoparticles removal.
The present study investigates how well the light quality (white, blue, and red light) affects th... more The present study investigates how well the light quality (white, blue, and red light) affects the growth and biochemical profiling of freshwater microalga Scenedesmus obliquus grown on aquaculture wastewater as a nutrient source in a biocathode microbial fuel cell (MFC). The findings show that the electrochemical behaviour of the MFCs varied with the use of different wavelengths, suggesting that light quality and photosynthetic evolved oxygen increased MFC voltage. Sc. obliquus showed the highest percentage of nutrient removal for blue light-operated biocathode MFC. Blue light maximized biomass production with a cell density of 1.54 ± 0.065 OD680 and Chl-a concentration of 12 ± 1.2 mgL − 1 during 6-day cultivation. Valorization of aquaculture using MFC proved successful in nutrient recovery and microalgae biomass production, primarily upon exposure to blue light.
Nanodyes are a new class of hazardous materials that are used in textile coloring. Their small si... more Nanodyes are a new class of hazardous materials that are used in textile coloring. Their small size, color, stability and high dispersion characteristics pose a huge threat if they are released in open water systems. The aim of the present study is to test electron beam irradiation, bioflocculation and their sequential use for nanodye removal. The nanodye was obtained from a factory and was characterized using UV-visible spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, dynamic light scattering, zeta potential and energy dispersive X-ray (EDX). The obtained results show that applying 7.5 kGy electron beam irradiation results in complete color removal in 10 min for 50 and 100 ppm nanodye, while at 200 and 400 ppm concentrations, the decolorization reaches 90% but leaving a residual brownish color. Adding 5 mg mL −1 of Serratia marcescens N2 biosurfactant resulted in agglomeration of 80% dye removal for 400 ppm nanodye after 24 h. On the other hand, the use of sequential electron beam and bioflocculation led to an initial removal of 80% in 1 h. The residual dyes were tested for toxicity on normal dermal HFB4 cells. The toxicity result was 1.19% after electron beam treatment, while those for sequential treatment and bioflocculation were 6.28 and 6.9%, respectively. It can be concluded that electron beam technology provides fast and highly efficient nanodye removal, while biosurfactants offer a low-cost, eco-friendly approach with a chance for dye retrieval.
Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquacultur... more Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquaculture industry as an antifungal agent, however, it can accumulate in fish and pose toxicity. The present work aims to remove MG in Microbial Fuel Cell (MFC) as a sustainable and eco-friendly solution. Out of six samples, the highest malachite green degradation was obtained by a sample obtained from Robiki tannery site in agar plates in 24 h at 37 °C. Robiki sample was used to inoculate the anodic chamber in Microbial Fuel cell, the resulting average electricity production was 195.76 mV for two weeks. The decolorization average was almost 88%. The predominant bacteria responsible for MG decolorization and electricity production were identified using 16S rRNA as Shewanella chilikensis strain MG22 (Accession no. OP795826) and formed a heavy biofilm on the anode. At the end of the decolorization process, MG was added again for re-use of water. The results showed efficiency for re-use 3 times. To ensure the sterility of treated water for re-use, both UV and filter sterilization were used, the latter proved more efficient. The obtained results are promising, MFC can be used as recirculating aquaculture system (RAS). The same aquaculture water can be treated multiple times which provides a sustainable solution for water conservation.
World Journal of Microbiology and Biotechnology, 2023
The increase in using antibiotics, especially Azithromycin have increased steadily since the begi... more The increase in using antibiotics, especially Azithromycin have increased steadily since the beginning of COVID19 pandemic. This increase has led to its presence in water systems which consequently led to its presence upon using this water for irrigation. The aim of the present work is to study the impact of irrigation using Azithromycin containing water on soil microbial community and its catabolic activity in the presence of phenolic wastes as compost. Wild berry, red grapes, pomegranate, and spent tea waste were added to soil and the degradation was monitored after 5 and 7 days at ambient and high temperatures. The results obtained show that at 30oC, soil microbial community collectively was able to degrade Azithromycin, while at 40oC, addition of spent tea as compost was needed to reach higher degradation. To ensure that the degradation was biotic and depended on degradation by indigenous microflora, a 25 kGy irradiation dose was used to kill the microorganisms in the soil and this was used as negative control. The residual antibiotic was assayed using UV spectroscopy and High Performance Liquid Chromatography (HPLC). Indication of Azithromycin presence was studied using Fourier Transform Infrared Spectroscopy (FTIR) peaks and the same pattern was obtained using the 3 used detection methods, the ability to assign the peaks even in the presence of soil and not to have any overlaps, gives the chance to study this result in depth to prepare IR based sensor for quick sensing of antibiotic in environmental samples.
World journal of microbiology & biotechnology incorporating the MIRCEN Journal of applied microbiology and biotechnology/World journal of microbiology & biotechnology, Jul 2, 2024
The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilizati... more The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilization of red cabbage extract (RCE) within bacterial cellulose (BC) to detect contamination and gamma radiation exposure in cucumbers. The results obtained show a sensitivity to pH changes for RCE in its aqueous form and that incorporated within BC films (RCE-BC), both showed color change correlated to bacterial growth (R 2 = 0.91), this was supported with increase in pH values from 2 to 12 (R 2 = 0.98). RCE and RCE-BC exposure to gamma radiation (0, 2.5, 5, 10, 15, 20, 25 kGy) resulted in gradual decrease in color that was more evident in RCE aqueous samples. To sense bacterial contamination of cucumbers, the total count was followed at 0, 5, 10 and 15 days in cold storage conditions and was found to reach 9.13 and 5.47 log cfu/mL for non-irradiated and 2 kGy irradiated samples, respectively. The main isolates detected throughout this storage period were identified as Pseudomonas fluorescens, Erwinia sp. Pantoea agglomerans using matrix assisted laser desorption ionization-time of flight-ms (MALDI-TOF-MS). Bacterial growth in stored irradiated cucumbers was detected by color change within 5 and 10 days of storage, after which there was no evident change. This is very useful since contamination within the early days of storage cannot be sensed with the naked eye. This study is the first to highlight utilizing RCE and RCE-BC as eco-friendly pH-sensing indicator films for intelligent food packaging to detect both food contamination and gamma preservation for refrigerator stored cucumbers.
The present study investigates how well the light quality (white, blue, and red light) affects th... more The present study investigates how well the light quality (white, blue, and red light) affects the growth and biochemical profiling of freshwater microalga Scenedesmus obliquus grown on aquaculture wastewater as a nutrient source in a biocathode microbial fuel cell (MFC). The findings show that the electrochemical behaviour of the MFCs varied with the use of different wavelengths, suggesting that light quality and photosynthetic evolved oxygen increased MFC voltage. Sc. obliquus showed the highest percentage of nutrient removal for blue light-operated biocathode MFC. Blue light maximized biomass production with a cell density of 1.54 ± 0.065 OD680 and Chl-a concentration of 12 ± 1.2 mgL − 1 during 6-day cultivation. Valorization of aquaculture using MFC proved successful in nutrient recovery and microalgae biomass production, primarily upon exposure to blue light.
The increase in using antibiotics, especially Azithromycin have increased steadily since the begi... more The increase in using antibiotics, especially Azithromycin have increased steadily since the beginning of COVID19 pandemic. This increase has led to its presence in water systems which consequently led to its presence upon using this water for irrigation. The aim of the present work is to study the impact of irrigation using Azithromycin containing water on soil microbial community and its catabolic activity in the presence of phenolic wastes as compost. Wild berry, red grapes, pomegranate, and spent tea waste were added to soil and the degradation was monitored after 5 and 7 days at ambient and high temperatures. The results obtained show that at 30 °C, soil microbial community collectively was able to degrade Azithromycin, while at 40 °C, addition of spent tea as compost was needed to reach higher degradation. To ensure that the degradation was biotic and depended on degradation by indigenous microflora, a 25 kGy irradiation dose was used to kill the microorganisms in the soil and...
Textile wastewater still poses a huge environmental problem due to its high water consumption and... more Textile wastewater still poses a huge environmental problem due to its high water consumption and high effluent release that is full of toxic chemicals. In the present study, different approaches were studied to layout an operating procedure for textile wastewater treatment in order to obtain treated wastewater that is safe for non-potable uses. Our approach depended on (1) co-substrate to biostimulate indigenous microbial textile wastewater community by adding Tryptone Soy Broth (TSB) and TSB supplemented with 1% glucose, (2) co-culture (bioaugmentation) with Bacillus spizizenii DN cells (previously isolated, identified and characterized as efficient decolorizing bacteria), and (3) co-metabolites using Bacillus spizizenii DN metabolites. The obtained results show that using Bacillus spizizenii DN cells resulted in 97.78% decolorization while adding Bacillus spizizenii DN metabolites resulted in 82.92% decolorization, both after 48 h incubation under microaerophilic conditions. The ...
MFCs have the potential to revolutionise wastewater treatment and catalyse a change in attitude t... more MFCs have the potential to revolutionise wastewater treatment and catalyse a change in attitude towards wastewater as a commodity. It has been observed that domestic wastewater contains approximately 7.6 kJ/L of energy (Heidrich et al., 2011). In large-scale settings, wastewater could be used as an energy resource, offering huge savings in terms of cost and environmental burden. The major challenges facing the implementation of MFCs into wastewater treatment are scale up and energy harvesting/storage. In this study, a modular 20L air-breathing microbial fuel cell was developed alongside a smart energy harvesting (EH) system incorporating AI. The 20L air breathing MFC consists of modular cathode cassettes that enables easy maintenance and scale up to suit adaptive or changing end user requirements. PVDF/Stainless steel mesh cathodes are fabricated using phase inversion and oxygen reduction reaction catalysts incorporated in the polymeric matrix. Custom made carbon fibre brush electro...
Microbial biocathodes are gaining interest due to their low cost, environmentally friendliness an... more Microbial biocathodes are gaining interest due to their low cost, environmentally friendliness and sustainable nature. In this study, activated sludge from a textile treatment plant was enriched by chronoamperometry over 70 days to select for electroactive bacteria for use as a cathode catalyst in microbial fuel cells (MFC) designed for azo dye degradation in the anode chamber. The resultant biofilm produced an average peak current of 0.7 mA during the enrichment and produced a maximum power density of 64.6±3.5 mW m-2 compared to platinum (72.7±1.2 mW m-2) in a MFC. The acclimated biocathode eliminated start-up lag and decreased the activation overpotential at the cathode. The rate of dye decolourisation at the anode was similar in both platinum and biocathode MFCs. Activation losses were lower for the biocathode than with platinum suggesting that the bacteria act as true cathode catalysts. The microbial community analysis of the initial sludge sample and enriched samples revealed t...
Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquacultur... more Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquaculture industry as an antifungal agent, however, it can accumulate in fish and pose toxicity. The present work aims to remove MG in Microbial Fuel Cell (MFC) as a sustainable and eco-friendly solution. Out of six samples, the highest malachite green degradation was obtained by a sample obtained from Robiki tannery site in agar plates in 24 h at 37 °C. Robiki sample was used to inoculate the anodic chamber in Microbial Fuel cell, the resulting average electricity production was 195.76 mV for two weeks. The decolorization average was almost 88%. The predominant bacteria responsible for MG decolorization and electricity production were identified using 16S rRNA as Shewanella chilikensis strain MG22 (Accession no. OP795826) and formed a heavy biofilm on the anode. At the end of the decolorization process, MG was added again for re-use of water. The results showed efficiency for re-use 3 times. To...
World Journal of Microbiology and Biotechnology, 2024
The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilizati... more The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilization of red cabbage extract (RCE) within bacterial cellulose (BC) to detect contamination and gamma radiation exposure in cucumbers. The results obtained show a sensitivity to pH changes for RCE in its aqueous form and that incorporated within BC films (RCE-BC), both showed color change correlated to bacterial growth (R 2 = 0.91), this was supported with increase in pH values from 2 to 12 (R 2 = 0.98). RCE and RCE-BC exposure to gamma radiation (0, 2.5, 5, 10, 15, 20, 25 kGy) resulted in gradual decrease in color that was more evident in RCE aqueous samples. To sense bacterial contamination of cucumbers, the total count was followed at 0, 5, 10 and 15 days in cold storage conditions and was found to reach 9.13 and 5.47 log cfu/mL for non-irradiated and 2 kGy irradiated samples, respectively. The main isolates detected throughout this storage period were identified as Pseudomonas fluorescens, Erwinia sp. Pantoea agglomerans using matrix assisted laser desorption ionization-time of flight-ms (MALDI-TOF-MS). Bacterial growth in stored irradiated cucumbers was detected by color change within 5 and 10 days of storage, after which there was no evident change. This is very useful since contamination within the early days of storage cannot be sensed with the naked eye. This study is the first to highlight utilizing RCE and RCE-BC as eco-friendly pH-sensing indicator films for intelligent food packaging to detect both food contamination and gamma preservation for refrigerator stored cucumbers.
Biofilm-mediated strategy was studied for ZnO nanoparticle removal from aqueous media. Bacillus s... more Biofilm-mediated strategy was studied for ZnO nanoparticle removal from aqueous media. Bacillus subtilis isolated from the soil rhizosphere was selected based on its high viscosity (133 Pa/s) of the cultivated culture and biofilm formation. The bacterium was exposed to gamma-irradiation to enhance EPS production along with its cultivation in EPS-producing media. The results show an increase in viscosity that reached 160 Pa/s at 2 kGy. EPS production increased from 4.45 to 7.95 mg/mL and the protein/carbohydrate ratio increased from 3 to 4.4 which reflects the stickiness of EPS. Thermal Gravimetric Analysis (TGA) showed 2 phase weight loss for gamma irradiated EPS and defined protein peaks when characterized using Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF). Native and gamma-irradiated Bacillus subtilis cells with their enhanced EPS were grown as a biofilm on sterile waste gauze fabric, Scanning Electron Microscopy (SEM) showed an increased biofilm attachment in gamma-irradiated samples. The latter was used for the removal of ZnO NP from aqueous media. Energy dispersive X-ray (EDX) mapping confirms that ZnO NPs were entrapped within the carbon and oxygen elements forming the biofilm with net intensities of 14.04, 1713, and 1190, respectively. The results confirm that biofilm-mediated strategy is effective in nanoparticles removal.
The present study investigates how well the light quality (white, blue, and red light) affects th... more The present study investigates how well the light quality (white, blue, and red light) affects the growth and biochemical profiling of freshwater microalga Scenedesmus obliquus grown on aquaculture wastewater as a nutrient source in a biocathode microbial fuel cell (MFC). The findings show that the electrochemical behaviour of the MFCs varied with the use of different wavelengths, suggesting that light quality and photosynthetic evolved oxygen increased MFC voltage. Sc. obliquus showed the highest percentage of nutrient removal for blue light-operated biocathode MFC. Blue light maximized biomass production with a cell density of 1.54 ± 0.065 OD680 and Chl-a concentration of 12 ± 1.2 mgL − 1 during 6-day cultivation. Valorization of aquaculture using MFC proved successful in nutrient recovery and microalgae biomass production, primarily upon exposure to blue light.
Nanodyes are a new class of hazardous materials that are used in textile coloring. Their small si... more Nanodyes are a new class of hazardous materials that are used in textile coloring. Their small size, color, stability and high dispersion characteristics pose a huge threat if they are released in open water systems. The aim of the present study is to test electron beam irradiation, bioflocculation and their sequential use for nanodye removal. The nanodye was obtained from a factory and was characterized using UV-visible spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, dynamic light scattering, zeta potential and energy dispersive X-ray (EDX). The obtained results show that applying 7.5 kGy electron beam irradiation results in complete color removal in 10 min for 50 and 100 ppm nanodye, while at 200 and 400 ppm concentrations, the decolorization reaches 90% but leaving a residual brownish color. Adding 5 mg mL −1 of Serratia marcescens N2 biosurfactant resulted in agglomeration of 80% dye removal for 400 ppm nanodye after 24 h. On the other hand, the use of sequential electron beam and bioflocculation led to an initial removal of 80% in 1 h. The residual dyes were tested for toxicity on normal dermal HFB4 cells. The toxicity result was 1.19% after electron beam treatment, while those for sequential treatment and bioflocculation were 6.28 and 6.9%, respectively. It can be concluded that electron beam technology provides fast and highly efficient nanodye removal, while biosurfactants offer a low-cost, eco-friendly approach with a chance for dye retrieval.
Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquacultur... more Malachite Green (MG) dye of the triphenylmethane group is a toxic compound used in the aquaculture industry as an antifungal agent, however, it can accumulate in fish and pose toxicity. The present work aims to remove MG in Microbial Fuel Cell (MFC) as a sustainable and eco-friendly solution. Out of six samples, the highest malachite green degradation was obtained by a sample obtained from Robiki tannery site in agar plates in 24 h at 37 °C. Robiki sample was used to inoculate the anodic chamber in Microbial Fuel cell, the resulting average electricity production was 195.76 mV for two weeks. The decolorization average was almost 88%. The predominant bacteria responsible for MG decolorization and electricity production were identified using 16S rRNA as Shewanella chilikensis strain MG22 (Accession no. OP795826) and formed a heavy biofilm on the anode. At the end of the decolorization process, MG was added again for re-use of water. The results showed efficiency for re-use 3 times. To ensure the sterility of treated water for re-use, both UV and filter sterilization were used, the latter proved more efficient. The obtained results are promising, MFC can be used as recirculating aquaculture system (RAS). The same aquaculture water can be treated multiple times which provides a sustainable solution for water conservation.
World Journal of Microbiology and Biotechnology, 2023
The increase in using antibiotics, especially Azithromycin have increased steadily since the begi... more The increase in using antibiotics, especially Azithromycin have increased steadily since the beginning of COVID19 pandemic. This increase has led to its presence in water systems which consequently led to its presence upon using this water for irrigation. The aim of the present work is to study the impact of irrigation using Azithromycin containing water on soil microbial community and its catabolic activity in the presence of phenolic wastes as compost. Wild berry, red grapes, pomegranate, and spent tea waste were added to soil and the degradation was monitored after 5 and 7 days at ambient and high temperatures. The results obtained show that at 30oC, soil microbial community collectively was able to degrade Azithromycin, while at 40oC, addition of spent tea as compost was needed to reach higher degradation. To ensure that the degradation was biotic and depended on degradation by indigenous microflora, a 25 kGy irradiation dose was used to kill the microorganisms in the soil and this was used as negative control. The residual antibiotic was assayed using UV spectroscopy and High Performance Liquid Chromatography (HPLC). Indication of Azithromycin presence was studied using Fourier Transform Infrared Spectroscopy (FTIR) peaks and the same pattern was obtained using the 3 used detection methods, the ability to assign the peaks even in the presence of soil and not to have any overlaps, gives the chance to study this result in depth to prepare IR based sensor for quick sensing of antibiotic in environmental samples.
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